The overall goal of this project is to test the efficacy of newly developed small, nonpeptide gonadotropin-releasing hormone (GnRH) antagonists, in suppressing reproductive hormone secretion in primates. Compounds are being administered to adult male rhesus monkeys, and blood samples collected to assess the response of LH and testosterone to each. Development of effective compounds will provide new tools for suppressing reproductive hormone secretion for contraceptive purposes, control of reproductive hormone secretion in various cancers, and will also provide new tools for examining the effects of GnRH in the central nervous system. FUNDING Merck Research Laboratories PUBLICATIONS None